A citizen science program has revealed the decline of one of the country’s most important chalk rivers after Environment Agency officials claimed it had not deteriorated. The SmartRivers program run by the charity WildFish, which studies freshwater invertebrates, has reported “large declines relative to chemical pressure” on the River Avon in Wiltshire. Its data indicates a decline in the river’s condition over the past five years.
The charity wrote a report on its findings after conservation groups said they were told at an Environment Agency meeting in August that “the water quality of the Avon is not has not deteriorated over the last five years. David Holroyd, water quality manager for the Wiltshire Fishery Association, said the number of invertebrates collected in the spring and autumn samples of 2019 and 2023 at 11 sites in the upper Avon had shown a decline.
He said the invertebrates were “the canary in the coal mine” and that data suggested they were being “poisoned by chemicals in the river”.
WildFish says the findings highlight the crucial role citizen scientists play in monitoring river health after a decline in the number of tests carried out by regulators over the past decade. The SmartRivers program in England, Wales and Scotland now covers 95 rivers, according to a new report from the charity WildFish.
Freshwater invertebrates are the basis of the aquatic food ecosystem, ranging from river flies and beetles to molluscs, worms and crustaceans. In the most recent results for all rivers monitored in 2022, volunteers found 268 different invertebrate species and counted 343,077 specimens. Invertebrate species have different tolerances to pollution. Analyzing the species present and their numbers helps identify pressures on water quality from agriculture, wastewater discharges and runoff from roads and residential areas.
Janina Gray, head of science and environmental policy at WildFish, said the ecological state of a river had been assessed under the Water Framework Directive, a European Union directive transposed into the legislation in England and Wales after Brexit. She said current assessments “don’t set the bar high enough.”
At the August meeting, the Environment Agency had argued that the Avon had not deteriorated under the Water Framework Directive classification, Gray said, adding: “It is frustrating that the river declines from year to year and that legislation does not protect it. It is one of the most protected rivers in this country. It is very diverse in terms of fish population. If we fail to protect the Avon, there is probably not much hope for many other rivers. We need a comprehensive monitoring network to be able to determine where problems are occurring, which is why SmartRivers are so important.
Gray said WildFish was now working with the Environment Agency and other partners to identify pressures on the river. An Environment Agency spokesperson said: “On the River Avon we are working with partners across the region to explore how best to use citizen science evidence alongside our own monitoring data to further improve the understanding of water quality. »
Recent analysis by WildFish found that every river sample from the Windermere catchment intended for the SmartRivers program had been affected by United Utilities’ wastewater treatment works. Pollution-sensitive river fly species were found to show declines of up to 76% compared to suitable upstream habitat.
United Utilities said the plants were operating in accordance with environmental permits.